1. Field of the Invention
The present invention relates to a method for controlling a plurality of devices provided with a communication function. Also, the present invention relates to a device that is used in implementing the method.
2. Description of Related Art
In recent years, distributed power sources such as solar power and wind power are becoming more widely used. However, with power sources utilizing such renewable energy, power supply tends to be unstable, and there is concern that an existing electric power grid will become unstable when such power sources are connected to the electric power grid on a large-scale. As a countermeasure to this, conventionally, a plurality of measurement devices are disposed in the electric power grid, and the power supply situation is constantly monitored.
The plurality of measurement devices need to perform a predetermined measurement at the same timing. It has been proposed to utilize the time information of a GPS (Global Positioning System), for example, in order to match the timing of measurement devices provided at separate locations. Alternatively, proposals such as matching the timing of the measurement devices by separately providing a monitoring device for comprehensively managing the plurality of measurement devices, or using one of the plurality of measurement devices as a master device and placing the other devices under the management of the master device have been made.
However, there is a problem with the above conventional methods in that the system as a whole tends to become large-scale and costs increase. Another problem is a lack of flexibility in dealing with situations in which there is a fault (or a program change) involving one or more of the devices.